Free and open source desktop and Web GIS solutions

Community-based development through collaboration amongst software developers and researchers distributed globally has led to a wealth of feature-rich applications of Free and Open Source Software for Geoinformatics (FOSS4G). In the FOSS4G, development model online source code repository, mailing lists, and a Wiki provide the software developers and users with a virtual and ubiquitous platform for the implementation of new methods, algorithms, and tools as well as for refinement and enhancements of the existing code. For end users, this development model provides highly interoperable, sophisticated software at no cost. This approach is both flexible and immune to vendor lock-ins. Further, the reproducibility of results and quality assessment of methods is greatly facilitated since full access to the underlying algorithms is guaranteed. The source code is typically published under free and open source software licenses with end-user rights to run the program for any purpose, to study how the program works, to adapt it, and to redistribute copies including modifications.